Printing impression plate and process of making same



PRINTING IMPRESSION PLATE AND PROCESS OF MAKING SAME A TH E.

5 @@FFl-*Z 5 7/111 www@ l: @SEWER -I5 @@@WEM A7 ATTORNEYS July 24, 1928. 1,677,929

W. J. PIPPERT PRINTING IMPRESSION PLATE AND PRocEss oF uAxING sum Filed Jan. 28, 1927 3 sheets-sheet 2 WIFI-5- 9 7 7"' IIJIQ -7 f/ "1 IIIIIIIINPIIMN] i 7 It olcmlwm@ ff 75 :ffvfszggrufyl INVENTOR wrmess '7 lMLA/5 PHJ/DMT ATTORNYS July 24, 1928. 1,677,929

w. J. PlPPER-r PRINTING IMPRESSION PLATE AND PROCESS OF IAKING SAME Filed Jan. 28, 1927 3 Sheets-Sheet 3 ATTORNEYS titi Patented July 24, i928.

WILLIS J. PIPPERT, OF IRIDLONVILLE, MAINE.

PATENT OFFICE.

PRINTING IMPRESSION PLATE AND PROCESS OF MAKING SAME.

Application led January 28, 1927. Serial No. 164,145.

This invention relates to plates or forms for printing or like work and the process of making same and is particularly luseful in connection with printing designs upon papers and other materials. It is also .useful in connection wit-h printing upon articles having varying thickness, such as paper bags, foldable cartons and the like.

The object of the invention is 'to repro.- duce by printing label designs, picture trade marks, advertising or other matter upon paper or other material so as to obtain an exact reproduction thereof not only in outline but also in the color shade which 1s usually required in applying printed matter to paper. The invention, in its broadest sense, contemplates the preparation ofan electroplate, type or other original printing plate of the matter desired to be reproduced and ultimately by a series of intermediate steps preparing from such original plate a rubber printing surface or plate and utilizing the same as a printing surface for applying the matter to be reproduced to the article which is to bear the reproduction.

Fig. l is a longitudinal section of the electrotype matrix and bag; Fig. 2 is a face view of the matrix; Fig. 3 is a cross-section on the line 3 3 of Fig. 2; Fig. 4 represents the saine view as Fig. 3 with the rubber sheet, screen and paper backing. applied to the matrix; Fig. 5 is a similar view of Fig. 4 after the parts have been sub]ected to pressure; Fig.A 6 is a View .of the rubber printing plate after being stripped from the matrix; Fig. 7 is a cross-section on the lines 7 7 of Fig. 6; Fig. 8 represents a holder` with the rubber printing plate fixed thereto; Fig. 9 is a section on lines 99 of Fig. 8.

Y The steps which are followed in the preparation of the rubber printing plate are as follows:

An electroplate, type or other original printing plate of the matter to be reproduced is prepared by any approved method. In the drawing, for the purpose of illustration, l indicates an electroplate carrying in the top surface thereof the impression of the matter to be ultimately reproduced. stereotype matrix is then formed following any one of the known. processes of preparing stereotypes. Such a stereotype matrix is preferably formed by locking the electro-- plate l in a form and then beating moist Hong with a stiftl brush into the depressions 2 of theoriginal plate 1 until such depressions' are entirely filled. The flong is then subjected to heat and baked until it is entirely free from moisture producing a inatrix 3 having the exact impression permanent-ly formed therein as is contained in the face of the original plate 1 including all the varying depths and high areas thereon. A sheet 4 of cheese cloth is then laid on the back of the matrix. A back 5 of stereotype metal Vis-then cast to a thickness of about three-sixteenths of an inch on the back of the matrix 3' and on top of the cloth 4 thereon which metal provides a support for the matrix and keeps the same smooth and flat during subsequent use thereof. The matrix 3 is then stripped from the face of the electi'oplate l and the face thereof is coated with graphite. A sheetr of pure gum or unvulcanized rubber 6, about one-eighth of an inch in thickness and slightly larger than that portion of thesurface of the matrix bearing the depression, is laid over the face 3a of the matrix 3. The periphery of the rubber sheet is then lined or framed with a flexible material 7 such as strip cork or liiioleum which acts to slightly resist the extension of the rubber sheet 3 during subsequent treatment. The flexible material 7 is preferably slightly thicker than the rubber sheet 6 so that its top surface extends slightly above the top surface of the rubber sheet 6. A section of closely woven nonstretchable apertured screen 8, preferably of the type which is used in Fourdrinier paper machines is cut to about the width and twice as long as the matrix and is placed over the rubber sheet and a. sheet of tissue paper 9 is placed on top of the wire and over the rubber sheet 6. The assembled parts in the positions illustrated in Fig. 4 are placed in a vulcanizer and pressure applied thereto so that the base of the rubber sheet 6, next to the matrix 3, is forced into the depressions thereof and the surface of the rubber sheet 6, next to the wire support 8, is forced between the interstices of the support 8. rlhe rubber while maintained in this condition is then vulcanized which usually occurs in about 15 to 20 minutes under eighty pounds steam pressure. The assembled-parts after the rubber has been vulcanized are removed from the vulcanizer and the rubber sheet 6, which has now taken an exact and permanent impression 6a of the matrix 3, is 'stripped therefrom. It will be found that the rubber sheet 6 in Sti addition to .having permanently embedded therein the impression of the matrix is also securely embedded into the screen or support 8, the rubber having penetrated the 1nterstices thereof and forming a continuous rubber coating 9 on the back of the screen 8. .The fiexible material 7 is then removed from around the rubber plate 10 and the edges 11 of the rubber plate'are trimmed closely to the impression carried thereby as shown at 12 in Fig. 9.

The finished rubber plate 10 will exhibit in great detail the exact impression contained in the original plate l and also, of course, the exact matter which is to be reproduced by printing.

Rubber printing plates made according to this invention will containv on the surface thereof all of the details of the original matter to be reproduced as illustrated in the electrotype or other original form. ln subsequent use for printing, the rubber plate will make an exact impression of the matter intended to be reproduced, including light and heavy impressions, inasmuch as the surface of the rubber plate will vary in corresponding degree to the various heights and depths of the original electrotype and there- 4by control the amount of ink which is deposited upon the material being printed upon. lit Will also be understood that the final product of this process-the rubber printing plate-has a flexible printing surf face and. will not only print successfully on plate sheets but also on collapsed paper bags, cartons and the like which when folded have varying thicknesses at the portions thereof which are to obtain an ink impression.

The graphite which is applied to the face of the martix 3 keeps the rubber sheet 1 from unduly sticking thereto and the sheet of paper 9 is applied to the back of the screen 8 so that the rubber forced therethrough will not stick to the plate of the vulcanizer. 'llhe lug like formations 13 represent rubber which has been pressed from between the abutting edges of the framing material 7 during the pressure treatment in the vulcanizer and are trimmed away after the framing material 7 is removed.

The plate 10 having been vulcanized by the foregoing steps may now be utilized for printing purposes either by attaching it to a block for fiat printing or to a suitable frame for utilization in the rotary press. A suitable metal frame 14 for use in rotary printing machines is illustrated in Fig. 9 having the slot 15 through which one of the free ends 16 of the wire support 8 is threaded whereupon the wire and rubber plate are laid over the surface of the frame 14 and the other free end of the wire 8 is threaded through the slot 17 in the frame 14 and then through the slot 18 and finally around the edge 19.

This invention may alsobe utilized in connection with the preparation of plates adapted for use in water marking paper. instance, a rubber plate prepared according* to this invention may be positioned at a convenient point in the path of travel of a moist paper sheet during its formation on a paper machine so that it will constantly rotate over the travelling web and compress the moist web to show the design of the plate after the web has been dried.

What I claim is:

1. The process of preparing an impression plate which consists in covering the face of a matrix with an elastic material, arranging a flexibleiframe about said elastic material to control the linal shape thereof, applying a section of apertured material to the top of the elastic material, applying pressure to the assembled parts to force the face. of the elastic material into the depressions of the matrix and the back of the elastic material through the said perforations, to form a continuous layer of elastic material over the apertured material, treating said elastic material to permanentize such impressions and to retain the apertured material embedded therein and stripping the elastic material, after it has acquired its permanent condition, from said matrix.

2. The process of preparing an impression plate which consists in applying a sheet of unvulcanized rubber to the face of a matrix arranging a frame of flexible material around the rubber sheet to prevent spreading of the latter upon vulcanizing and a section of screen on the top of the rubber sheet, applying pressure to the edges of the rubber sheet against said flexible material and the assembled part so as to force the surface of the rubber sheet in contact with the matrix into the depressions thereof and to embed the screening into theback of the rubber sheet, vulcanizing the rubber sheet while under pressure to cause the rubber sheet to permanently retain the impression of the matrix, and finally stripping the rubber sheet and screening from the matrix.

3. An elastic impression' surface comprising a sheet of flexible and resilient material having a backing of non-stretchable screening imbedded therein, said'screening providing the sole support for said resilient material and being of such length as to overlap the ends of said sheet, thereby providing means for attaching it to a printing block.

lin testimony whereof, lf have hereunto set my hand.

WILLIS J. PIPPERT.

Thus for 

